The objective

Understanding neural mechanisms is a vital element in the practice of medicine and in important clinical research. Measuring, assessing, documenting and interpreting sensation and pain responses in humans is critical in understanding the underlying normal physiological and psychological processes, and disease mechanisms.

Sensation and pain pathways

Our skin contains different types of receptors. These are innervated by specific nerve fibers and respond to distinct physical stimuli. Pain-specific information originates in peripheral nociceptors and is then conveyed to the central nervous system (spinal cord and brain) via small-caliber Ad and C nerve fibers, which may be damaged in certain disorders. This damage, called neuropathy, manifests as diminished or spontaneous sensations, and in neuropathic pain. Thermal testing allows assessment of small fiber functionality, to better understand the mechanisms of neuropathy and neuropathic pain development. Also, testing pain responses in pain states, among them chronic pain that originates in the central nervous system e.g. central post-stroke pain, can provide us with valuable information about disease mechanisms, progression and treatment responses.

Medoc’s devices in the research arena

Medoc systems allow to perform various modalities of thermal, pressure, and vibration testing to be implemented in different research settings:

Quantitative Sensory Testing

Quantitative sensory testing (QST) is a set of methods that provide information regarding the relationship between stimulus and perception (psychophysics) in a controlled and systematic manner. QST is regarded as the gold standard in detecting and characterizing the function of the sensory nervous system in health and disease. Specifically, the function of Ad and C fibers can be assessed using simple thermal QST, such as sensation and pain thresholds, and pain tolerance.

Experimental pain

Administration of experimental pain allows us to learn about pain processing in health in normal-state and under specific conditions, as well as in various disorders of the peripheral and central nervous system. Experimental pain, as delivered by Medoc’s devices, is controlled, standardized and validated, and hence, allows to reduce bias and data contamination. Experimental pain may come in the form of thermal or pressure pain, depending on the mechanism to be tested, and the specific hypothesis. Experimentally induced pain can also serve as an aversive stimulus in psychology studies and can be precisely timed along with other stimuli in or outside of the scanner using external control.

Dynamic QST

Medoc’s systems provide researchers with tools to study central pain processing. Fast temperature change rates and rapid stimuli in the temporal summation of pain (TSP) protocol allow evaluating the subjective tendency to amplify pain through the mechanism of wind-up. This is a marker for central sensitization. Our TSA2 dual-thermode configuration can deliver two concomitant pain stimuli in the conditioned pain modulation (CPM) protocol, which provides information regarding the individual ability to inhibit pain. CPM is also known as diffuse noxious inhibitory control, a mechanism of endogenous analgesia. Our flexible software allows you to customize protocols to explore various additional dynamic phenomena such as offset analgesia, allodynia, hyperalgesia, and more.

Pain Evoked Potentials

Contact Heat Evoked Potentials (CHEPs) tests can be performed using the Medoc TSA2 with the CHEPS accessory. Researchers adopting CHEPs can investigate the neural correlates of pain in real-time, in a non-invasive manner, by recording EEG responses to rapid heat stimuli. CHEPs allows a quantitative and objective assessment of pain processing.

Use in Functional Magnetic Resonance Imaging environment

Medoc’s devices can be fitted with fMRI-compatible thermodes and accessories, enabling researchers to administer thermal painful and non-painful stimuli in an imaging environment and study the associated brain responses in high spatial resolution.

Why Use Medoc’s Solutions?

Modularity. Our thermal devices can be fitted with a choice of thermode sizes and configurations. Our software contains flexible heat and cold stimulation paradigms, including method-of-limits, method-of-levels, thermo-sensory limen and more. Users can also control their device via TTL and third-party software e.g. MATLAB™ and E-Prime™.

fMRI compatibility. TSA2 can be purchased with a set of fMRI-compatible thermodes and safely used in fMRI environment.

Accuracy. With an absolute accuracy threshold of ±0.3°C, our thermal QST solutions ensure the inner repeatability and validity of your experiments.​

Validity. Our software contains an integrated database of validated and peer-reviewed normative data based on age. Our devices have been used in over 1,500 academic and industrial studies spanning the past 30 years.

Safety. The thermode temperatures in our devices are constantly monitored in real-time and have both software and hardware fail-safe mechanisms, ensuring participant safety. There are built-in settings of cut-off temperatures and stimulation durations.

User-friendliness. We designed our systems with software and hardware ease-of-use in mind, for both academic and private research.